fault.c 22.5 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
/*
 * Based on arch/arm/mm/fault.c
 *
 * Copyright (C) 1995  Linus Torvalds
 * Copyright (C) 1995-2004 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

21
#include <linux/extable.h>
22 23 24 25 26 27 28
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/page-flags.h>
29
#include <linux/sched/signal.h>
30
#include <linux/sched/debug.h>
31 32
#include <linux/highmem.h>
#include <linux/perf_event.h>
33
#include <linux/preempt.h>
34
#include <linux/hugetlb.h>
35

36
#include <asm/bug.h>
37
#include <asm/cmpxchg.h>
38
#include <asm/cpufeature.h>
39 40
#include <asm/exception.h>
#include <asm/debug-monitors.h>
41
#include <asm/esr.h>
42
#include <asm/sysreg.h>
43 44 45
#include <asm/system_misc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
46
#include <asm/traps.h>
47

48 49
#include <acpi/ghes.h>

50 51 52 53 54 55 56 57 58 59 60 61 62 63
struct fault_info {
	int	(*fn)(unsigned long addr, unsigned int esr,
		      struct pt_regs *regs);
	int	sig;
	int	code;
	const char *name;
};

static const struct fault_info fault_info[];

static inline const struct fault_info *esr_to_fault_info(unsigned int esr)
{
	return fault_info + (esr & 63);
}
64

65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)
{
	int ret = 0;

	/* kprobe_running() needs smp_processor_id() */
	if (!user_mode(regs)) {
		preempt_disable();
		if (kprobe_running() && kprobe_fault_handler(regs, esr))
			ret = 1;
		preempt_enable();
	}

	return ret;
}
#else
static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)
{
	return 0;
}
#endif

87 88 89 90 91 92 93 94 95 96 97 98 99 100
static void data_abort_decode(unsigned int esr)
{
	pr_alert("Data abort info:\n");

	if (esr & ESR_ELx_ISV) {
		pr_alert("  Access size = %u byte(s)\n",
			 1U << ((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT));
		pr_alert("  SSE = %lu, SRT = %lu\n",
			 (esr & ESR_ELx_SSE) >> ESR_ELx_SSE_SHIFT,
			 (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT);
		pr_alert("  SF = %lu, AR = %lu\n",
			 (esr & ESR_ELx_SF) >> ESR_ELx_SF_SHIFT,
			 (esr & ESR_ELx_AR) >> ESR_ELx_AR_SHIFT);
	} else {
101
		pr_alert("  ISV = 0, ISS = 0x%08lx\n", esr & ESR_ELx_ISS_MASK);
102 103 104 105 106 107 108 109 110 111 112
	}

	pr_alert("  CM = %lu, WnR = %lu\n",
		 (esr & ESR_ELx_CM) >> ESR_ELx_CM_SHIFT,
		 (esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT);
}

static void mem_abort_decode(unsigned int esr)
{
	pr_alert("Mem abort info:\n");

113
	pr_alert("  ESR = 0x%08x\n", esr);
114 115 116 117 118 119 120 121 122 123 124 125 126 127
	pr_alert("  Exception class = %s, IL = %u bits\n",
		 esr_get_class_string(esr),
		 (esr & ESR_ELx_IL) ? 32 : 16);
	pr_alert("  SET = %lu, FnV = %lu\n",
		 (esr & ESR_ELx_SET_MASK) >> ESR_ELx_SET_SHIFT,
		 (esr & ESR_ELx_FnV) >> ESR_ELx_FnV_SHIFT);
	pr_alert("  EA = %lu, S1PTW = %lu\n",
		 (esr & ESR_ELx_EA) >> ESR_ELx_EA_SHIFT,
		 (esr & ESR_ELx_S1PTW) >> ESR_ELx_S1PTW_SHIFT);

	if (esr_is_data_abort(esr))
		data_abort_decode(esr);
}

128
/*
129
 * Dump out the page tables associated with 'addr' in the currently active mm.
130
 */
131
void show_pte(unsigned long addr)
132
{
133
	struct mm_struct *mm;
134 135
	pgd_t *pgdp;
	pgd_t pgd;
136

137 138 139 140 141 142 143 144 145 146
	if (addr < TASK_SIZE) {
		/* TTBR0 */
		mm = current->active_mm;
		if (mm == &init_mm) {
			pr_alert("[%016lx] user address but active_mm is swapper\n",
				 addr);
			return;
		}
	} else if (addr >= VA_START) {
		/* TTBR1 */
147
		mm = &init_mm;
148 149 150 151 152
	} else {
		pr_alert("[%016lx] address between user and kernel address ranges\n",
			 addr);
		return;
	}
153

154
	pr_alert("%s pgtable: %luk pages, %u-bit VAs, pgdp = %p\n",
155 156
		 mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K,
		 VA_BITS, mm->pgd);
157 158 159
	pgdp = pgd_offset(mm, addr);
	pgd = READ_ONCE(*pgdp);
	pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd));
160 161

	do {
162 163 164
		pud_t *pudp, pud;
		pmd_t *pmdp, pmd;
		pte_t *ptep, pte;
165

166
		if (pgd_none(pgd) || pgd_bad(pgd))
167 168
			break;

169 170 171 172
		pudp = pud_offset(pgdp, addr);
		pud = READ_ONCE(*pudp);
		pr_cont(", pud=%016llx", pud_val(pud));
		if (pud_none(pud) || pud_bad(pud))
173 174
			break;

175 176 177 178
		pmdp = pmd_offset(pudp, addr);
		pmd = READ_ONCE(*pmdp);
		pr_cont(", pmd=%016llx", pmd_val(pmd));
		if (pmd_none(pmd) || pmd_bad(pmd))
179 180
			break;

181 182 183 184
		ptep = pte_offset_map(pmdp, addr);
		pte = READ_ONCE(*ptep);
		pr_cont(", pte=%016llx", pte_val(pte));
		pte_unmap(ptep);
185 186
	} while(0);

187
	pr_cont("\n");
188 189
}

190 191 192 193 194 195 196 197 198 199 200 201 202 203
/*
 * This function sets the access flags (dirty, accessed), as well as write
 * permission, and only to a more permissive setting.
 *
 * It needs to cope with hardware update of the accessed/dirty state by other
 * agents in the system and can safely skip the __sync_icache_dcache() call as,
 * like set_pte_at(), the PTE is never changed from no-exec to exec here.
 *
 * Returns whether or not the PTE actually changed.
 */
int ptep_set_access_flags(struct vm_area_struct *vma,
			  unsigned long address, pte_t *ptep,
			  pte_t entry, int dirty)
{
204
	pteval_t old_pteval, pteval;
205
	pte_t pte = READ_ONCE(*ptep);
206

207
	if (pte_same(pte, entry))
208 209 210
		return 0;

	/* only preserve the access flags and write permission */
211
	pte_val(entry) &= PTE_RDONLY | PTE_AF | PTE_WRITE | PTE_DIRTY;
212 213 214

	/*
	 * Setting the flags must be done atomically to avoid racing with the
215 216 217
	 * hardware update of the access/dirty state. The PTE_RDONLY bit must
	 * be set to the most permissive (lowest value) of *ptep and entry
	 * (calculated as: a & b == ~(~a | ~b)).
218
	 */
219
	pte_val(entry) ^= PTE_RDONLY;
220
	pteval = pte_val(pte);
221 222 223 224 225 226 227
	do {
		old_pteval = pteval;
		pteval ^= PTE_RDONLY;
		pteval |= pte_val(entry);
		pteval ^= PTE_RDONLY;
		pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval);
	} while (pteval != old_pteval);
228 229 230 231 232

	flush_tlb_fix_spurious_fault(vma, address);
	return 1;
}

233 234 235 236 237
static bool is_el1_instruction_abort(unsigned int esr)
{
	return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR;
}

238 239 240
static inline bool is_el1_permission_fault(unsigned int esr,
					   struct pt_regs *regs,
					   unsigned long addr)
241 242 243 244 245 246 247 248 249 250
{
	unsigned int ec       = ESR_ELx_EC(esr);
	unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;

	if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR)
		return false;

	if (fsc_type == ESR_ELx_FSC_PERM)
		return true;

251
	if (addr < TASK_SIZE && system_uses_ttbr0_pan())
252 253 254 255 256 257
		return fsc_type == ESR_ELx_FSC_FAULT &&
			(regs->pstate & PSR_PAN_BIT);

	return false;
}

258 259
static void __do_kernel_fault(unsigned long addr, unsigned int esr,
			      struct pt_regs *regs)
260
{
261 262
	const char *msg;

263 264
	/*
	 * Are we prepared to handle this kernel fault?
265
	 * We are almost certainly not prepared to handle instruction faults.
266
	 */
267
	if (!is_el1_instruction_abort(esr) && fixup_exception(regs))
268 269 270
		return;

	bust_spinlocks(1);
271

272
	if (is_el1_permission_fault(esr, regs, addr)) {
273 274 275 276 277 278 279 280 281 282 283 284
		if (esr & ESR_ELx_WNR)
			msg = "write to read-only memory";
		else
			msg = "read from unreadable memory";
	} else if (addr < PAGE_SIZE) {
		msg = "NULL pointer dereference";
	} else {
		msg = "paging request";
	}

	pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg,
		 addr);
285

286 287
	mem_abort_decode(esr);

288
	show_pte(addr);
289 290 291 292 293
	die("Oops", regs, esr);
	bust_spinlocks(0);
	do_exit(SIGKILL);
}

294
static void __do_user_fault(struct siginfo *info, unsigned int esr)
295
{
296 297 298
	current->thread.fault_address = (unsigned long)info->si_addr;
	current->thread.fault_code = esr;
	arm64_force_sig_info(info, esr_to_fault_info(esr)->name, current);
299 300
}

301
static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
302 303 304 305 306
{
	/*
	 * If we are in kernel mode at this point, we have no context to
	 * handle this fault with.
	 */
307
	if (user_mode(regs)) {
308 309 310 311 312 313 314 315 316
		const struct fault_info *inf = esr_to_fault_info(esr);
		struct siginfo si = {
			.si_signo	= inf->sig,
			.si_code	= inf->code,
			.si_addr	= (void __user *)addr,
		};

		__do_user_fault(&si, esr);
	} else {
317
		__do_kernel_fault(addr, esr, regs);
318
	}
319 320 321 322 323 324
}

#define VM_FAULT_BADMAP		0x010000
#define VM_FAULT_BADACCESS	0x020000

static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
325
			   unsigned int mm_flags, unsigned long vm_flags,
326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
			   struct task_struct *tsk)
{
	struct vm_area_struct *vma;
	int fault;

	vma = find_vma(mm, addr);
	fault = VM_FAULT_BADMAP;
	if (unlikely(!vma))
		goto out;
	if (unlikely(vma->vm_start > addr))
		goto check_stack;

	/*
	 * Ok, we have a good vm_area for this memory access, so we can handle
	 * it.
	 */
good_area:
343 344
	/*
	 * Check that the permissions on the VMA allow for the fault which
345
	 * occurred.
346 347
	 */
	if (!(vma->vm_flags & vm_flags)) {
348 349 350 351
		fault = VM_FAULT_BADACCESS;
		goto out;
	}

352
	return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags);
353 354 355 356 357 358 359 360

check_stack:
	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
		goto good_area;
out:
	return fault;
}

M
Mark Rutland 已提交
361 362 363 364 365
static bool is_el0_instruction_abort(unsigned int esr)
{
	return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
}

366 367 368 369 370
static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
				   struct pt_regs *regs)
{
	struct task_struct *tsk;
	struct mm_struct *mm;
371 372
	struct siginfo si;
	int fault, major = 0;
373
	unsigned long vm_flags = VM_READ | VM_WRITE;
374 375
	unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;

376 377 378
	if (notify_page_fault(regs, esr))
		return 0;

379 380 381 382 383 384 385
	tsk = current;
	mm  = tsk->mm;

	/*
	 * If we're in an interrupt or have no user context, we must not take
	 * the fault.
	 */
386
	if (faulthandler_disabled() || !mm)
387 388
		goto no_context;

389 390 391
	if (user_mode(regs))
		mm_flags |= FAULT_FLAG_USER;

M
Mark Rutland 已提交
392
	if (is_el0_instruction_abort(esr)) {
393
		vm_flags = VM_EXEC;
M
Mark Rutland 已提交
394
	} else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
395 396 397 398
		vm_flags = VM_WRITE;
		mm_flags |= FAULT_FLAG_WRITE;
	}

399
	if (addr < TASK_SIZE && is_el1_permission_fault(esr, regs, addr)) {
400 401
		/* regs->orig_addr_limit may be 0 if we entered from EL0 */
		if (regs->orig_addr_limit == KERNEL_DS)
402
			die("Accessing user space memory with fs=KERNEL_DS", regs, esr);
403

404 405 406
		if (is_el1_instruction_abort(esr))
			die("Attempting to execute userspace memory", regs, esr);

407
		if (!search_exception_tables(regs->pc))
408
			die("Accessing user space memory outside uaccess.h routines", regs, esr);
409
	}
410

411 412
	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);

413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434
	/*
	 * As per x86, we may deadlock here. However, since the kernel only
	 * validly references user space from well defined areas of the code,
	 * we can bug out early if this is from code which shouldn't.
	 */
	if (!down_read_trylock(&mm->mmap_sem)) {
		if (!user_mode(regs) && !search_exception_tables(regs->pc))
			goto no_context;
retry:
		down_read(&mm->mmap_sem);
	} else {
		/*
		 * The above down_read_trylock() might have succeeded in which
		 * case, we'll have missed the might_sleep() from down_read().
		 */
		might_sleep();
#ifdef CONFIG_DEBUG_VM
		if (!user_mode(regs) && !search_exception_tables(regs->pc))
			goto no_context;
#endif
	}

435
	fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk);
436
	major |= fault & VM_FAULT_MAJOR;
437

438 439 440 441 442 443 444
	if (fault & VM_FAULT_RETRY) {
		/*
		 * If we need to retry but a fatal signal is pending,
		 * handle the signal first. We do not need to release
		 * the mmap_sem because it would already be released
		 * in __lock_page_or_retry in mm/filemap.c.
		 */
445 446 447
		if (fatal_signal_pending(current)) {
			if (!user_mode(regs))
				goto no_context;
448
			return 0;
449
		}
450 451 452 453 454 455 456 457 458 459 460 461

		/*
		 * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of
		 * starvation.
		 */
		if (mm_flags & FAULT_FLAG_ALLOW_RETRY) {
			mm_flags &= ~FAULT_FLAG_ALLOW_RETRY;
			mm_flags |= FAULT_FLAG_TRIED;
			goto retry;
		}
	}
	up_read(&mm->mmap_sem);
462 463

	/*
464
	 * Handle the "normal" (no error) case first.
465
	 */
466 467 468 469 470 471 472 473 474
	if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
			      VM_FAULT_BADACCESS)))) {
		/*
		 * Major/minor page fault accounting is only done
		 * once. If we go through a retry, it is extremely
		 * likely that the page will be found in page cache at
		 * that point.
		 */
		if (major) {
475 476 477 478 479 480 481 482 483 484
			tsk->maj_flt++;
			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
				      addr);
		} else {
			tsk->min_flt++;
			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
				      addr);
		}

		return 0;
485
	}
486

487 488 489 490 491 492 493
	/*
	 * If we are in kernel mode at this point, we have no context to
	 * handle this fault with.
	 */
	if (!user_mode(regs))
		goto no_context;

494 495 496 497 498 499 500 501 502 503
	if (fault & VM_FAULT_OOM) {
		/*
		 * We ran out of memory, call the OOM killer, and return to
		 * userspace (which will retry the fault, or kill us if we got
		 * oom-killed).
		 */
		pagefault_out_of_memory();
		return 0;
	}

504 505 506
	clear_siginfo(&si);
	si.si_addr = (void __user *)addr;

507 508 509 510 511
	if (fault & VM_FAULT_SIGBUS) {
		/*
		 * We had some memory, but were unable to successfully fix up
		 * this page fault.
		 */
512 513 514 515 516 517 518 519 520 521 522 523
		si.si_signo	= SIGBUS;
		si.si_code	= BUS_ADRERR;
	} else if (fault & VM_FAULT_HWPOISON_LARGE) {
		unsigned int hindex = VM_FAULT_GET_HINDEX(fault);

		si.si_signo	= SIGBUS;
		si.si_code	= BUS_MCEERR_AR;
		si.si_addr_lsb	= hstate_index_to_shift(hindex);
	} else if (fault & VM_FAULT_HWPOISON) {
		si.si_signo	= SIGBUS;
		si.si_code	= BUS_MCEERR_AR;
		si.si_addr_lsb	= PAGE_SHIFT;
524 525 526 527 528
	} else {
		/*
		 * Something tried to access memory that isn't in our memory
		 * map.
		 */
529 530 531
		si.si_signo	= SIGSEGV;
		si.si_code	= fault == VM_FAULT_BADACCESS ?
				  SEGV_ACCERR : SEGV_MAPERR;
532 533
	}

534
	__do_user_fault(&si, esr);
535 536 537
	return 0;

no_context:
538
	__do_kernel_fault(addr, esr, regs);
539 540 541 542 543 544 545 546 547 548 549 550 551 552
	return 0;
}

static int __kprobes do_translation_fault(unsigned long addr,
					  unsigned int esr,
					  struct pt_regs *regs)
{
	if (addr < TASK_SIZE)
		return do_page_fault(addr, esr, regs);

	do_bad_area(addr, esr, regs);
	return 0;
}

553 554 555 556 557 558 559
static int do_alignment_fault(unsigned long addr, unsigned int esr,
			      struct pt_regs *regs)
{
	do_bad_area(addr, esr, regs);
	return 0;
}

560 561
static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
{
562
	return 1; /* "fault" */
563 564
}

565 566 567 568 569 570 571
static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
{
	struct siginfo info;
	const struct fault_info *inf;

	inf = esr_to_fault_info(esr);

572 573 574 575 576 577 578 579 580
	/*
	 * Synchronous aborts may interrupt code which had interrupts masked.
	 * Before calling out into the wider kernel tell the interested
	 * subsystems.
	 */
	if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) {
		if (interrupts_enabled(regs))
			nmi_enter();

581
		ghes_notify_sea();
582 583 584 585 586

		if (interrupts_enabled(regs))
			nmi_exit();
	}

587
	info.si_signo = inf->sig;
588
	info.si_errno = 0;
589
	info.si_code  = inf->code;
590 591 592 593
	if (esr & ESR_ELx_FnV)
		info.si_addr = NULL;
	else
		info.si_addr  = (void __user *)addr;
594
	arm64_notify_die(inf->name, regs, &info, esr);
595

596
	return 0;
597 598
}

599
static const struct fault_info fault_info[] = {
600 601 602 603
	{ do_bad,		SIGKILL, SI_KERNEL,	"ttbr address size fault"	},
	{ do_bad,		SIGKILL, SI_KERNEL,	"level 1 address size fault"	},
	{ do_bad,		SIGKILL, SI_KERNEL,	"level 2 address size fault"	},
	{ do_bad,		SIGKILL, SI_KERNEL,	"level 3 address size fault"	},
604
	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level 0 translation fault"	},
605 606
	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level 1 translation fault"	},
	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level 2 translation fault"	},
607
	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level 3 translation fault"	},
608
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 8"			},
S
Steve Capper 已提交
609 610
	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 1 access flag fault"	},
	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 2 access flag fault"	},
611
	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 3 access flag fault"	},
612
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 12"			},
S
Steve Capper 已提交
613 614
	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 1 permission fault"	},
	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 2 permission fault"	},
615
	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 3 permission fault"	},
616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632
	{ do_sea,		SIGBUS,  BUS_OBJERR,	"synchronous external abort"	},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 17"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 18"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 19"			},
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 0 (translation table walk)"	},
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 1 (translation table walk)"	},
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 2 (translation table walk)"	},
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 3 (translation table walk)"	},
	{ do_sea,		SIGBUS,  BUS_OBJERR,	"synchronous parity or ECC error" },	// Reserved when RAS is implemented
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 25"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 26"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 27"			},
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 0 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 1 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 2 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
	{ do_sea,		SIGKILL, SI_KERNEL,	"level 3 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 32"			},
633
	{ do_alignment_fault,	SIGBUS,  BUS_ADRALN,	"alignment fault"		},
634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 34"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 35"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 36"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 37"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 38"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 39"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 40"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 41"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 42"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 43"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 44"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 45"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 46"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 47"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"TLB conflict abort"		},
	{ do_bad,		SIGKILL, SI_KERNEL,	"Unsupported atomic hardware update fault"	},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 50"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 51"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"implementation fault (lockdown abort)" },
	{ do_bad,		SIGBUS,  BUS_OBJERR,	"implementation fault (unsupported exclusive)" },
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 54"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 55"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 56"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 57"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 58" 			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 59"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 60"			},
	{ do_bad,		SIGKILL, SI_KERNEL,	"section domain fault"		},
	{ do_bad,		SIGKILL, SI_KERNEL,	"page domain fault"		},
	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 63"			},
664 665
};

666 667 668 669 670 671 672 673 674 675
int handle_guest_sea(phys_addr_t addr, unsigned int esr)
{
	int ret = -ENOENT;

	if (IS_ENABLED(CONFIG_ACPI_APEI_SEA))
		ret = ghes_notify_sea();

	return ret;
}

676 677 678
asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
					 struct pt_regs *regs)
{
679
	const struct fault_info *inf = esr_to_fault_info(esr);
680 681 682 683 684
	struct siginfo info;

	if (!inf->fn(addr, esr, regs))
		return;

685 686 687
	if (!user_mode(regs)) {
		pr_alert("Unhandled fault at 0x%016lx\n", addr);
		mem_abort_decode(esr);
688
		show_pte(addr);
689
	}
690

691 692 693 694
	info.si_signo = inf->sig;
	info.si_errno = 0;
	info.si_code  = inf->code;
	info.si_addr  = (void __user *)addr;
695
	arm64_notify_die(inf->name, regs, &info, esr);
696 697
}

698 699 700 701 702 703
asmlinkage void __exception do_el0_irq_bp_hardening(void)
{
	/* PC has already been checked in entry.S */
	arm64_apply_bp_hardening();
}

704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720
asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr,
						   unsigned int esr,
						   struct pt_regs *regs)
{
	/*
	 * We've taken an instruction abort from userspace and not yet
	 * re-enabled IRQs. If the address is a kernel address, apply
	 * BP hardening prior to enabling IRQs and pre-emption.
	 */
	if (addr > TASK_SIZE)
		arm64_apply_bp_hardening();

	local_irq_enable();
	do_mem_abort(addr, esr, regs);
}


721 722 723 724 725
asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
					   unsigned int esr,
					   struct pt_regs *regs)
{
	struct siginfo info;
726

727 728 729 730 731 732
	if (user_mode(regs)) {
		if (instruction_pointer(regs) > TASK_SIZE)
			arm64_apply_bp_hardening();
		local_irq_enable();
	}

733 734 735 736
	info.si_signo = SIGBUS;
	info.si_errno = 0;
	info.si_code  = BUS_ADRALN;
	info.si_addr  = (void __user *)addr;
737
	arm64_notify_die("SP/PC alignment exception", regs, &info, esr);
738 739
}

740 741 742 743 744 745 746 747 748
int __init early_brk64(unsigned long addr, unsigned int esr,
		       struct pt_regs *regs);

/*
 * __refdata because early_brk64 is __init, but the reference to it is
 * clobbered at arch_initcall time.
 * See traps.c and debug-monitors.c:debug_traps_init().
 */
static struct fault_info __refdata debug_fault_info[] = {
749 750 751
	{ do_bad,	SIGTRAP,	TRAP_HWBKPT,	"hardware breakpoint"	},
	{ do_bad,	SIGTRAP,	TRAP_HWBKPT,	"hardware single-step"	},
	{ do_bad,	SIGTRAP,	TRAP_HWBKPT,	"hardware watchpoint"	},
752
	{ do_bad,	SIGKILL,	SI_KERNEL,	"unknown 3"		},
753
	{ do_bad,	SIGTRAP,	TRAP_BRKPT,	"aarch32 BKPT"		},
754
	{ do_bad,	SIGKILL,	SI_KERNEL,	"aarch32 vector catch"	},
755
	{ early_brk64,	SIGTRAP,	TRAP_BRKPT,	"aarch64 BRK"		},
756
	{ do_bad,	SIGKILL,	SI_KERNEL,	"unknown 7"		},
757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776
};

void __init hook_debug_fault_code(int nr,
				  int (*fn)(unsigned long, unsigned int, struct pt_regs *),
				  int sig, int code, const char *name)
{
	BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info));

	debug_fault_info[nr].fn		= fn;
	debug_fault_info[nr].sig	= sig;
	debug_fault_info[nr].code	= code;
	debug_fault_info[nr].name	= name;
}

asmlinkage int __exception do_debug_exception(unsigned long addr,
					      unsigned int esr,
					      struct pt_regs *regs)
{
	const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
	struct siginfo info;
777
	int rv;
778

779 780 781 782 783 784
	/*
	 * Tell lockdep we disabled irqs in entry.S. Do nothing if they were
	 * already disabled to preserve the last enabled/disabled addresses.
	 */
	if (interrupts_enabled(regs))
		trace_hardirqs_off();
785

786 787 788
	if (user_mode(regs) && instruction_pointer(regs) > TASK_SIZE)
		arm64_apply_bp_hardening();

789 790 791 792 793 794 795
	if (!inf->fn(addr, esr, regs)) {
		rv = 1;
	} else {
		info.si_signo = inf->sig;
		info.si_errno = 0;
		info.si_code  = inf->code;
		info.si_addr  = (void __user *)addr;
796
		arm64_notify_die(inf->name, regs, &info, esr);
797 798
		rv = 0;
	}
799

800 801
	if (interrupts_enabled(regs))
		trace_hardirqs_on();
802

803
	return rv;
804
}
805
NOKPROBE_SYMBOL(do_debug_exception);
806 807

#ifdef CONFIG_ARM64_PAN
808
void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused)
809
{
810 811 812 813 814 815
	/*
	 * We modify PSTATE. This won't work from irq context as the PSTATE
	 * is discarded once we return from the exception.
	 */
	WARN_ON_ONCE(in_interrupt());

816
	config_sctlr_el1(SCTLR_EL1_SPAN, 0);
817
	asm(SET_PSTATE_PAN(1));
818 819
}
#endif /* CONFIG_ARM64_PAN */